This invention relates generally to an apparatus for lifting a weight from a first level to a second level and in particular to a wheelchair lift for lifting a wheelchair bound individual from street level into a transportation vehicle, such as a van.
For many years, disabled people had little or no disabled-accessible transportation or mobility technology available in the United States. Today, there are several companies that sell a conversion kit for a van that retrofits a wheelchair lift onto a van so that the disabled person has transportation that is wheelchair accessible. The problem is that the available conversion kits are not satisfying the needs of the disabled people. The satisfaction level of the customers is not very high due to high costs and inadequate lift systems.
These conventional van conversion kits have a number of problems that lead to the low customer satisfaction. First, these conventional van conversion kits are very expensive (about $10,000-$16,000). When combined with the cost of a new van ($30,000), the overall cost makes it very difficult for less wealthy disabled people to be able to afford to have a wheelchair accessible transportation vehicle. Thus, although the technology exists to provide disabled people with wheelchair accessible transportation, many disabled people cannot afford to have wheelchair accessible transportation.
In addition, the wheelchair lifting apparatus currently on the market require a large amount of vertical storage space that significantly decreases the amount of ground clearance of the vehicle into which they are installed. In particular, these conventional wheelchair lifting apparatus, when not in use, are stored underneath the van and hang down approximately 6-9 inches. Thus, the distance between the road or an obstacle and the bottom of the wheelchair lifting apparatus (the ground clearance) is small (e.g., about six inches or less). Thus, the wheelchair lifting apparatus may be easily damaged, such as by running over a log in the road, that may cost as much to fix as a new lifting apparatus. In addition, the large height of the conventional lifting apparatus units prevent these conventional lifting apparatus from being installed in any vehicles other than full-size vans since only vans have a clearance height (the distance between the bottom of the van and the ground) sufficient to accommodate the conventional lifting apparatus. In fact, most conventional lifting apparatus require a half ton van to be outfitted with a lift kit to raise them off the ground far enough to accommodate the lifting apparatus.
One conventional lifting apparatus made by Braun, has an outer case fabricated out of aluminum to make it easier to build. However, aluminum is a fairly soft metal so that this lifting apparatus may be easily damaged. These conventional wheelchair lifting apparatus also have lifting mechanisms that are dangerous and cannot adequately support unbalances loads. In particular, the conventional lifting mechanisms may fail and cause a wheelchair board person currently on the lifting apparatus to fall to the ground causing great bodily injury to person if the wheelchair is not properly located on the platform.
In addition, conventional lifting apparatus are not built with the safety of the disabled person in mind. For example, most of the conventional wheelchair lifting apparatus have some type of railing that the disabled person may hold onto, but most conventional lifting apparatus require another person to remove the railings from a storage location and secure them for the disabled person so that the lift cannot be safely operated by the disabled person alone. As another example, some conventional lifting apparatus use a single hydraulic cylinder connected to the center of the wheelchair lifting platform to lift the disabled person that may be unable to safely lift a wheelchair that is not exactly located on the middle of the platform. As another example, many conventional wheelchair lifting apparatus move the platform both vertically and horizontally at the same time in an arc so that the horizontal motion may cause the wheelchair to roll around the platform or even worse, fall off of the platform and possibly hurt the disabled person.
The conventional lifting apparatus also cannot be used for larger vertical lifts into vehicles such as trains, high platforms or motor homes. Thus, these conventional lifting apparatus cannot be used by customers in a snow belt region who require the lifting apparatus to be installed on a four wheel drive van that requires the disabled person to be lifted more than 32 inches. The maximum lifting height of the conventional lifting apparatus is about 30 inches. The conventional lifting apparatus also cannot accommodate an extra wide wheelchair (about 34 inches wide).
Thus, the conventional lifting apparatus have a number of problems and limitations that make them less than suitable for their disabled customers. Therefore, it is desirable to provide a disabled person lifting apparatus that overcomes the above problems and limitations with conventional wheelchair lifting apparatus and it is to this end that the present invention is directed.
The disabled person lifting apparatus in accordance with the invention overcomes many of the limitations, problems and safety concerns with conventional wheelchair lifting apparatus. The disabled person lifting apparatus also has many other advantages. The disabled person lifting apparatus may be stored, when not it use, either under the floor of the vehicle or in the floor of the vehicle. The storage of the lifting apparatus in the floor of the vehicle allows the disabled person on the platform of the lifting apparatus to be secured to the platform during the trip in the vehicle instead of rolling the disabled person off of the lifting platform into the vehicle. The storage of the lifting platform in the floor of the vehicle also permits the height of the disabled person during the vehicle trip to be adjusted using the lifting apparatus.
The lifting apparatus may also operate to lift people from only one side of the lifting apparatus closest to the vehicle so that the installation of the lifting apparatus does not interfere with the drive shaft of the vehicle. In addition, the lifting apparatus may be able to lift a disabled person to a wide variety of heights. While lifting the disabled person, the lifting apparatus moves only in a vertical direction so that the wheelchair is less likely to roll on the platform since there is no horizontal motion of the lifting apparatus. Thus, it is less likely that the wheelchair user may fall off of the platform of the lifting apparatus while being lifted into a vehicle. The lifting apparatus in accordance with the invention, however, may permit the horizontal movement of the platform prior to and after the lifting operation that increases the flexibility of the positioning of the lifting platform.
The lifting mechanism of the lifting apparatus may use a pair of lifting arms on each side of the platform to ensure a level, safe lift of the disabled person. The lifting mechanism may be driven by an electric motor or by a hydraulic ram. The lifting mechanism executes a 120xc2x0 positive force motion so that the platform moves solely in a vertical direction while the hydraulic arms are above or below the lifting platform. This motion provides a smooth, evenly applied lifting force during both the lifting and lowering of the platform. The lifting mechanism may be disengaged from the lifting arms and the lifting apparatus may be manually operated to provide a way of operating the lifting apparatus if the lifting mechanism fails.
The lifting apparatus may be used for various types of vehicles, such as vans, trains, recreational vehicles, automobiles, buses, as well as a short run of stairs. For larger vertical lifts, the lifting apparatus may have telescoping lifting arms so that the disabled person may be lifted up to higher distances than conventional lifting apparatus. Thus, the lifting apparatus may be used for a variety of different lifting uses. The lifting apparatus may be less than four inches in the vertical dimension when stored so that the distance between the lifting apparatus underneath a vehicle and the ground is increased so that the lifting apparatus is less likely to be damaged. The small vertical storage height of the lifting apparatus also makes it easier to install and less expensive since it does not require a reinforced metal cowling to protect it from damage due to impact with the ground. The smaller vertical height also permits less expensive, full size automobiles to be modified to include the lifting apparatus. In addition, the length and width of the lifting apparatus in accordance with the invention may be easily modified to accommodate the needs of the individual customers.
The lifting apparatus in accordance with the invention may lift a disabled person up to 34 vertical inches so that the lifting apparatus may be used in a four wheel modified van that is the usual transportation in an area with heavy snowfall each year. In fact, if the length of the platform of the lifting apparatus is increased by some amount, then the lifting height of the lifting apparatus is increased so that the lifting apparatus in accordance with the invention may have an adjustable maximum lifting height.